CD4+/CD45RO+: A Potential Biomarker of the Clinical Response to Glatiramer Acetate

Background: Glatiramer acetate (GA) is an effective treatment for the earliest stages of multiple sclerosis (MS)—clinically isolated syndrome (CIS) or clinically definite MS (CDMS). Objective: This study aims to determine the differences in the lymphocyte population (at baseline and the course of five years) between confirmed sustained progression (CSP) and non-CSP groups and to identify potential biomarkers among these parameters that can predict a positive response to the treatment. Methods: Twelve male and 60 female patients were included in the study. Peripheral blood samples were collected before and five years after treatment with GA. The authors compared lymphocyte parameters between the CSP and non-CSP groups by statistical analyses. Univariate and penalized logistic regression models were fitted to identify the best lymphocyte parameters at baseline and their combination for potential biomarkers. Subsequently, the ROC analysis was used to identify cut-offs for selected parameters. Results: The parameter CD4+/CD45RO+ was identified as the best single potential biomarker, demonstrating the ability to identify patients with CSP. Moreover, a combination of four lymphocyte parameters at baseline, relative lymphocyte counts, CD3+/CD69+, CD4+/CD45RO+, and CD4+/CD45RA+ab, was identified as a potential composite biomarker. This combination explains 23% of the variability in CSP, which is better than the best univariate parameter when compared to CD4+/CD45RO+ at baseline. Conclusions: The results suggest that other biomarkers can help monitor the conditions of patients and predict a favourable outcome.

Neuroendocrine differentiation markers guide treatment sequence selection in metastatic castration-resistant prostate cancer

BACKGROUND

To evaluate the value of the serum neuroendocrine differentiation (NED) markers in helping to select the best treatment sequence of abiraterone acetate (AA) and docetaxel-prednisone (DP) in mCRPC.

METHODS

Eighty-eight mCRPC patients were identified (42 in the DP-to-AA group and 46 in the AA-to-DP group). The serum levels of NED markers were measured before the first-line treatment in 88 patients and also before and after DP therapy in 38 patients. We determined their impact on OS, radiographic progression-free survival (rPFS), and PSA-PFS.

RESULTS

In men with an elevation of at least one NED marker (n = 46) before the first-line treatment, those who received AA and then DP had significantly better worse OS (21.7 months [95% CI 21.0-22.4] vs 19.9 months (95% CI 15.3-24.5); P = 0.023. In a multivariate Cox regression analysis, treatment sequencing selection (selecting DP-AA rather than AA-DP) independently predicted OS (HR 0.4, 95% CI 0.2-0.9, P = 0.035) in patients with an elevation of at least one NED marker. However, in the subgroup without NED marker elevation, there was no significant difference in clinical outcomes between AA-DP and DP-AA groups (all P > 0.05). In the group with continued NED marker evaluation during DP treatment, patients with higher baseline NED markers and obtaining PSA response to DP were more inclined to experience NED markers decline.

CONCLUSIONS

Elevated pretreatment serum NED markers might indicate mCRPC patients would get better clinical outcomes from DP-AA than AA-DP. In contrast, those without NED marker elevation had similar outcomes regardless of which agent was chosen first. mCRPC patients with elevated NED markers and chemotherapy response were more inclined to obtain NED markers decline during DP therapy, which could account for this phenomenon.

[THE STANDARD VALUES OF SUB-POPULATIONS OF T-HELPERS OF DIFFERENT LEVEL OF DIFFERENTIATION IN PERIPHERAL BLOOD]

The study was carried out to develop standard indicators of relative and absolute content of main populations of T-helpers in peripheral blood of conditionally healthy donors. The examination was implemented to sampling of 52 healthy individuals (29 males and 23 females) aged 18-65 years (median is 30 years). The multicolor cytofluorimetric analysis was applied using panel of following antibodies: CD45RA-FITC, CD62L-PE, CCR4-PerCP/Cy5.5; CCR6-PE/Cy7, CXCR3-APC, CD3-APC-AF750, CD4-Pacific Blue and CXCR5-Brilliant Violet 510TM. The T-helpers 1 were distributed in populations of cells with phenotypes CXCR5-CXCR3+CCR6-CCR4-, also containing Th9, and CXCR5-CXCR3+CCR6+CCR4- referred as Thl/Thl7. The Th2 were detected an the basis of availability of CCR4 at the absence of all other chemokin receptors. The Thi7, besides Thl/Thi7 mentioned above, were detected in composition of CXCR5-CXCR3-CCR6+CCR4- and CXCR5-CXCR3-CCR6+CCR4+. The last population also contained Th22. The follicular Th which expressed at their surface CXCR5, formed six cellular populations with following phenotypes: CXCR5+CXCR3-CCR6-CCR4- (Tfh/Tfh2), CXCR5+CXCR3-CCR6-CCR4+ (Tfh2), CXCR5+CXCR3-CCR6+CCR4- (Tfh17), CXCR5+CXCR3-CCR6+CCR4+ (Tfh17), CXCR5+CXCR3+CCR6-CCR4- (Tfh1) and CXCR5+CXCR3+CCR6+CCR4- (Tfh1/Tfh17). The relative and absolute content of T-helpers of mentioned phenotypes was established both within the framework of total population CD3+CD4+ of lymphocytes and among "naive" T-helpers (CD45RA-CD62L+), T-helpers of central (CD45RA-CD62L+) and effector (CD45RA- CD62L-) memory and also "terminal-differentiated" CD45RA-positive cells of effector memory with phenotype CD45RA+CD62L-. The study results can be applied as standard indicators under diagnostic of pathologic conditions of immune system.

Enhanced Osseointegration of Hierarchical Micro/Nanotopographic Titanium Fabricated by Microarc Oxidation and Electrochemical Treatment

Rapid osseointegration is recognized as a critical factor in determining the success rate of orthopedic and dental implants. Microarc oxidation (MAO) fabricated titanium oxide coatings with a porous topography have been proven to be a potent approach to enhance osteogenic capacity. Now we report two kinds of new hierarchical coatings with similar micromorphologies but different nanotopographies (i.e., MAO and MAO-AK coatings), and both coatings significantly promote cell attachment and osteogenic differentiation through mediating the integrin β1 signaling pathway. In this study, titanium with a unique hierarchical micro/nanomorphology surface was fabricated by a novel duplex coating process, that is, the first a titanium oxide layer was coated by MAO, and then the coating was electrochemically reduced in alkaline solution (MAO-AK). A series of in vitro stem cell differentiation and in vivo osseointegration experiments were carried out to evaluate the osteogenic capacity of the resulting coatings. In vitro, the initial adhesion of the canine bone marrow stem cells (BMSCs) seeded on the MAO and MAO-AK coatings was significantly enhanced, and cell proliferation was promoted. In addition, the expression levels of osteogenesis-related genes, osteorix, alkaline phosphates (ALP), osteopontin, and osteocalcin, in the canine BMSCs, were all up-regulated after incubation on these coatings, especially on the MAO-AK coating. Also, the in vitro ALP activity and mineralization capacity of canine BMSC cultured on the MAO-AK group was better than that on the MAO group. Furthermore, 6 weeks after insertion of the titanium implants into canine femurs, both the bone formation speed and the bone-implant contact ratio of the MAO-AK group were significantly higher than those of the MAO group. All these results suggest that this duplex coating process is promising for engineering titanium surfaces to promote osseointegration for dental and orthopedic applications.

Elevated survivin expression in peripheral blood mononuclear cells is central to collateral formation in coronary chronic total occlusion

Survivin is essential to angiogenesis and revascularization, but its role in coronary collateral formation remains unclear. The role of survivin in peripheral blood mononuclear cells (PBMCs) of coronary chronic total occlusion (CTO) patients was investigated. Coronary CTO patients (n=46; mean age 60.1±8.5, male 54.3%) (CTO group) and normal control patients (n=18; mean age 58.0±10.0, male 55.6%) underwent angiographic collateral vessel grading by Rentrop classification (C0 - C3) and provided peripheral blood between June 2006 and February 2007. Rat hind limb ischemia models were constructed using four equal groups of Sprague-Dawley rats (n=36): normal control, sham operation, operation and granulocyte macrophage colony-stimulating factor (GM-CSF). PBMC numbers and characteristics, collateral vessels, survivin, CD4, CD8, CD44, vascular endothelial growth factor (VEGF) and intercellular adhesion molecule-1 (ICAM-1) expression were determined using RT-PCR, flow cytometry, immunocytochemistry and western blot analysis. PBMC survivin mRNA and protein expression levels were higher in patients with good collateral circulation (C2 + C3) than in patients with no collateral flow (C0) (all P<0.05). Survivin single-positive and survivin and CD8, VEGF and ICAM-1 double-positive percentages were elevated in patients with good collateral circulation compared to those with normal and no collateral flow (all P<0.05), consistent with the rat model results, wherein higher survivin levels produced significantly larger and more visible collateral vessels. In conclusion, elevated survivin expression in PBMCs, particularly survivin and CD8, VEGF, and ICAM-1 double-positive PBMCs, may be crucial for good collateral formation in patients with coronary CTO, as confirmed by assessment of a rat model.

[The flow cytometry in diagnostic of sepsis in children of first year of life with congenital heart disease and operated in conditions of artificial circulation]

The study was organized to evaluate sensitivity and specificity of CD64 index and relative amount of HLA-DR+ monocytes in diagnostic of sepsis in children of first year of life after surgery correction if congenital heart disease in conditions of artificial circulation. To detect CD64 index the kit Leuko64 (Beckman Coulter USA) was applied. The relative amount of HLA-DR+ monocytes was measured by flow cytofluorimeter Navios (Beckman Coulter, USA) using combination of monoclonal antibodies CD14-APC, HLA-DR-PacificBlue, CD45-KrOr. The results of study established that CD64 index in the group with confirmed or supposed sepsis consisted 2.29 (1.96:3.32) that statistically is reliably higher (p = 0.001) than in group without sepsis. The study established no statistically reliable differences in concentration of C-reactive protein in blood serum (p-0.123), absolute amount of leukocytes in peripheral blood (p = 0.128), relative amount of HLA-DR+ monocytes (p = 0.789). It is demonstrated that value of CD64 index higher than 2.00 increases the risk of development of sepsis up to 9.4 times and can be used as a diagnostic criterion of sepsis (AUC = 0.895) with sensitivity up to 80% and specificity up to 90%. The negative prognostic significance of CD64 index and content of procalcitonin in relation to development of sepsis in children of first year of life operated in conditions of artificial circulation amounted to 74% and 76% and 77% and 64% in case of positive prognostic significance correspondingly.

The administration of milk fermented by the probiotic Lactobacillus casei CRL 431 exerts an immunomodulatory effect against a breast tumour in a mouse model

Antitumour activity is one of the health-promoting effects attributed to probiotics specially analysed from preclinical models, mostly murine. Here, the effect of milk fermented by the probiotic bacterium Lactobacillus casei CRL 431, on a murine breast cancer model was analysed. Mice were fed with milk fermented by Lactobacillus casei or unfermented milk before and after tumour injection. Rate of tumour development, cytokines in serum, IgA, CD4, CD8, F4/80 and cytokines positive cells in mammary glands were determined. Microvasculature in the tumour tissues was monitored. The effect of fermented milk administration after tumour injection was also evaluated. It was observed that probiotic administration delayed or blocked tumour development. This effect was associated to modulation of the immune response triggered by the tumour. The area occupied by blood vessels decreased in the tumours from mice given fermented milk which agrees with their small tumours, and fewer side effects. Finally, it was observed that probiotic administration after tumour detection was also beneficial to delay the tumour growth. In conclusion, we showed in this study the potential of milk fermented by the probiotic Lactobacillus casei CRL431 to stimulate the immune response against this breast tumour, avoiding or delaying its growth when it was preventively administrated and also when the administration started after tumour cells injection.

IL-7 dysregulation and loss of CD8+ T cell homeostasis in the monogenic human disease autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a monogenic autoimmune disease that is caused by mutations in the AIRE gene. Murine studies have linked AIRE to thymocyte selection and peripheral deletional tolerance, but the pathogenesis of the human disease remains unclear. In this study, we show that APECED patients have elevated IL-7 levels and a drastically decreased expression of IL-7R on CD8(+) T cells. This is associated with increased proliferation and a decreased expression of the negative TCR regulator CD5 in the CD45RO(-) subset. The CD45RO(-) cells also display oligoclonal expansions, decreased expression of the lymph node homing factors CCR7 and CD62L, and increased expression of perforin, consistent with the accumulation of highly differentiated effector cells. The CD45RO(-)CCR7(+)CD8(+) population of cells with markers characteristic of naive phenotype is also skewed, as shown by decreased expression of CD5 and increased expression of perforin. The putative CD31(+) recent thymic emigrant population is likewise affected. These data are consistent with IL-7 dysregulation inducing a decreased threshold of TCR signaling and self-antigen-driven proliferation, probably in synergy with the failed thymic selection. The resultant loss of CD8(+) T cell homeostasis is likely to play a significant role in the pathogenesis of APECED. Our findings may also hold lessons for other diseases in which the IL-7-IL-7R pathway has emerged as a risk factor.

Expression of surface markers on peripheral CD4+CD25high T cells in patients with atopic asthma: role of inhaled corticosteroid

BACKGROUND

CD4(+)CD25(+) regulatory T cells (Tregs) mediate immune suppression through cell-cell contact with surface molecules, particularly cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), glucocorticoid-induced tumor necrosis factor receptor family-related protein (GITR), and transforming growth factor beta (TGF-beta), but little is known about the exact role of Tregs in the pathogenesis of asthma. This study sought to characterize the expression of surface markers on peripheral blood mononuclear cells-derived Tregs in patients with atopic asthma and healthy subjects, and to investigate the effect of inhaled corticosteroid on them.

METHODS

The expression of surface molecules on CD4(+)CD25(high) Tregs was detected by flow cytometry. The effect of inhaled corticosteroid on expression of the surface molecules on Tregs was determined in vivo and in vitro. Total serum immunoglobulin E (IgE) and high-sensitivity C-reactive protein were measured by enzyme linked immunosorbent assay and latex enhanced immunoturbidimetric assay, respectively.

RESULTS

Equivalent numbers of peripheral Tregs were found in patients with atopic asthma (stable and acute) and healthy subjects. Tregs preferentially expressed CTLA-4, GITR, toll-like receptor 4 (TLR4), latency-associated peptide (LAP/TGF-beta1), and forkhead box P3 (FOXP3). Patients with acute asthma had decreased numbers of CD4(+)CD25(high)LAP(+) T cells compared to healthy subjects and stable asthmatics. Inhaled corticosteroid enhanced the percentage of Tregs expressing LAP in vivo and in vitro dose-dependently. Furthermore, the percentages of Tregs expressing LAP were negatively correlated with total serum IgE levels and severity of asthma, but positively correlated with forced expiratory volume in one second percentage of the predicted value in patients with asthma.

CONCLUSIONS

The results suggest that membrane-bound TGF-beta1 is a potential candidate for predicting the severity of asthma, and may contribute to the sustained remission of asthma. Strategies targeting Tregs on their surface markers, especially TGF-beta1, are promising for future therapy of asthma.

Increased frequency of CD4(+)CD25(high) Treg cells inhibit BCG-specific induction of IFN-gamma by CD4(+) T cells from TB patients

Cell-mediated immunity plays a considerable role in the protection against Mycobacterium tuberculosis infection. The immune response to tuberculosis (TB) was dominated by both CD4(+) T cells with the T helper 1 type cytokines and CD8(+) T cells. Recent studies have suggested that the circumstances in which protective or tissue-damaging T cell responses to microbes are affected by the activity of Treg (CD4(+)CD25(high)) cells. In the present study, we demonstrated that the frequencies of CD4(+)CD25(+) and CD4(+)CD25(high) T cells in TB patients were significantly higher compared to normal individuals. These Treg cells expressed CTLA-4 and Foxp3 at protein level and displayed activation and memory phenotypes as assessed by flow cytometric analysis. The frequencies of CD4(+)CD25(high)CTLA-4(+) and CD4(+)CD25(high)Foxp3(+) T cells within the total CD4(+) T cell population were significantly increased in the blood of TB patients compared to healthy donors. Moreover, the expression of GITR on Treg cells was higher in TB patients than in normal donors. The phenotypic analysis demonstrated that CD4(+)CD25(high) Treg expressed higher levels of CD45RO and HLA-DR, and lower levels of CD45RA compared to CD4(+)CD25(low) and CD4(+)CD25(-) T cells. The addition of CD4(+)CD25(high) T cells back to cultures could significantly suppress the antigen-specific production of IFN-gamma induced by BCG-stimulated CD4(+)CD25(-) T cells, suggesting that Treg might play a key role in the control of cellular immune responses in TB infection.

Proportions of circulating T cells with a regulatory cell phenotype increase with HIV-associated immune activation and remain high on antiretroviral therapy

OBJECTIVE

To examine the relationships between blood CD4 natural regulatory T (Treg) cells, plasma HIV RNA level, CD4 T-cell count and immune activation in untreated HIV-infected patients and immunodeficient patients beginning antiretroviral therapy (ART), using a novel phenotype to define Treg cells (CD25CD127CD4). Data were compared with established Treg cell markers (FoxP3, CTLA-4 and GITR).

METHODS

Twenty-nine untreated HIV-infected patients with CD4 T-cell counts of < 300 or > 400/microl were compared in a cross-sectional study and 12 patients beginning combination ART with < 100 CD4 T cells/mul were followed for 1 year on therapy. Three- and four-colour flow cytometry was used to quantitate proportions of Treg cells.

RESULTS

In control donors and patients with high CD4 T-cell counts, 28-89% (median 60%) of CD25CD127CD4 cells were FoxP3, but < 10% expressed GITR or CTLA-4. Immunodeficient patients also had CD4-negative lymphocytes with the phenotype FoxP3CD127. Proportions of CD25CD127 cells and activated (HLA-DR) cells in the CD4 T-cell population were increased in patients with low CD4 T cell counts. The proportion of CD25CD127CD4 T cells correlated positively with plasma HIV RNA level and CD4 T-cell activation, but inversely with CD4 T-cell count. Longitudinal studies of 12 patients receiving ART in two distinct cohorts (Western Australia and Malaysia) showed that the proportion of CD25CD127CD4 cells decreased slightly over time, but remained above levels seen in non-HIV controls.

CONCLUSIONS

Proportions of circulating T cells with a regulatory cell phenotype increase with HIV-associated immune activation and remain high after 1 year on ART.

Negative signaling contributes to T-cell anergy in trauma patients

OBJECTIVE

Maintenance of postinjury T-lymphocyte immune paralysis or anergy could result from failure to activate costimulatory receptors during T-cell receptor activation and/or from chronic stimulation of a competing set of elevated corepressor receptors. Our objective was to assess whether elevated posttrauma T-lymphocyte surface expression of corepressor receptors was associated with immunodepressed lymphocyte responses and corresponded to increased inhibitory and decreased activating signal transduction molecules.

DESIGN

Prospective observational study.

SETTING

University trauma intensive care unit and research laboratory.

PATIENTS

Sixty-one severe thermal and mechanical trauma patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Isolated trauma patients' and controls' peripheral blood T cells were assayed for negative and positive costimulation receptor expression. These receptor expression levels were compared (flow cytometry) between the two groups and correlated to T-cell levels of inhibitory and activating signal transduction molecules and proliferation capacity. Patients' proliferation hyporesponsive (anergic) T cells had increased expression of novel inhibitory receptors (corepressors) PD-1 (p < .05) and CD47 (p < .05) vs. patients' T-cell proliferation competent or controls' T cells. Patients' T-cell CD152 (CTLA-4) expression was also elevated vs. controls. Only patients' anergic T cells had simultaneously increased levels of the inhibitory signal transduction proteins, c-Cbl, a ubiquitin-ligase (p < .01) and SHP-1, a phosphatase (p < .01), concomitant to depressed phosphorylation of the activating signal kinases Erk, Zap70, and CD3Euro. T-cell receptor complex phosphorylation and activation of the interleukin-2 pivotal transcriptional complex protein CREB were also simultaneously depressed as c-Cbl and SHP-1 were elevated.

CONCLUSIONS

Up-regulated corepressor receptor expression is novelly shown to characterize trauma patients' anergic T cells and correlate with predominance of inhibitory overactivating signal transduction molecules during T-cell stimulation. This could contribute to postinjury immunosuppression.

The soluble forms of CD28, CD86 and CTLA-4 constitute possible immunological markers in patients with abdominal aortic aneurysm

OBJECTIVE

The T cell co-stimulatory factors CD28 and CTLA-4 and their ligands CD80 and CD86 occur as receptors on T cells and antigen-presenting cells and also in soluble forms in the circulation. We determined the levels of soluble co-stimulatory molecules in patients with abdominal aortic aneurysm (AAA) and normal individuals. We further correlated these soluble co-stimulatory molecules to other clinical parameters of importance such as age of the patient, presence of hypertension, size of the aneurysm and levels of matrix metalloproteinases-9 and C-reactive protein.

DESIGN, SETTING, SUBJECTS

This case-control study was designed to quantify the circulating levels of soluble co-stimulatory molecules by an in-house enzyme linked immunosorbent assay. A total of 314 subjects participated in the study including 100 patients and 214 normal controls. The statistical analysis was performed by Mann-Whitney test and Spearman's correlation rank test.

RESULTS

Our results show increased plasma levels of sCD28, sCD86 (P = 0.0001) and decreased plasma levels of sCTLA-4 (P = 0.0018) in the patients compared with normal individuals. The levels of these factors were not related to the age of the patient, size of aneurysm or levels of C-reactive protein in plasma. There was, however, a significant inverse relationship between the concentrations of sCTLA-4 and sCD80 with matrix metalloproteinase-9.

CONCLUSIONS

We suggest that soluble co-stimulatory molecules serve as biomarkers for the estimation of immune activation in AAA patients.

Soluble costimulatory factors sCD28, sCD80, sCD86 and sCD152 in relation to other markers of immune activation in patients with myasthenia gravis

The costimulatory factors CD28, CD80, CD86 and CD152 needed to start and turn off an immune response are present as membrane receptors and soluble proteins. There was no difference in the serum levels of soluble costimulatory molecules in 153 healthy controls and 118 patients with myasthenia gravis. However, we could confirm that the soluble forms of ICAM-1 and CD25 were increased in patients. The concentrations of the soluble costimulatory proteins seemed to be rather constant in individual patients, despite changes in clinical presentation. Thus, the soluble costimulatory factors do not seem to constitute reliable markers for disease activity in myasthenia gravis.

Diagnosis of Acute Renal Allograft Rejection by Analyzing Whole Blood mRNA Expression of Lymphocyte Marker Molecules

BACKGROUND

Currently, the diagnosis of acute rejection after kidney transplantation is based on a kidney biopsy taken after clinical rejection suspicion. A robust, noninvasive diagnostic method would allow easier and more frequent monitoring of the patient and the graft. Potentially, a straightforward method would be the analysis of lymphocyte marker molecule expression from whole blood samples.

METHODS

Whole blood samples were collected prospectively in a single kidney transplantation center from 50 adult kidney recipients transplanted between 2001 and 2005. The mRNA expression of granzyme B, perforin, FasL, granulysin, CD154, ICOS, CTLA4 and PD-1 were analyzed with real-time quantitative polymerase chain reaction.

RESULTS

The expression of ICOS and CD154 were significantly lower in rejection patients than in control patients (P<0.001). Both genes gave statistically significant area under receiver operating characteristic curve (AUC; 0.87, 0.88) with 84% sensitivity and 100% specificity for CD154 and 76% and 86% for ICOS, respectively. In paired rejection and postrejection therapy samples, the expression of both genes significantly increased during rejection therapy (P<0.001). When rejection patients were compared to patients biopsied because of other reasons of graft dysfunction, both CD154 and ICOS were lower in rejection patients but only CD154 was statistically significant (P=0.028, AUC=0.740, sensitivity 52%, specificity 90%). The other studied genes gave no consistent statistically significant results.

CONCLUSIONS

The whole blood gene expression quantities of costimulatory molecules CD154 and ICOS reasonably robustly differentiated rejection patients from control patients. The clinical use of the analysis is limited by poor capability to differentiate patients with rejection from patients with other causes of graft dysfunction.

Soluble CTLA-4 in autoimmune thyroid diseases: relationship with clinical status and possible role in the immune response dysregulation

CTLA-4 molecule, expressed by activated T and B lymphocytes, transduces an inhibitory signal. Increasing evidence showed CTLA-4 gene as an important susceptibility locus for autoimmune endocrinopathies and other autoimmune disorders. The aim is to evaluate the augmented sCTLA-4 serum levels in different autoimmune thyroid diseases when compared with normal donors or with non-autoimmune hyperthyroidism and to investigate the functional activities and suggest the possible pathogenetic role of sCTLA-4. We demonstrate the presence of a soluble form of CTLA-4 in 59/90 sera from patients with autoimmune thyroid diseases (both Graves' disease and autoimmune thyroiditis). sCTLA-4 levels were not related to specific clinical manifestations, such as clinical thyroid status (hypo- or hyperthyroidism), circulating thyroid hormones, or other clinical features (ophthalmopathy). sCTLA-4 production does not seem to be affected by disease evolution during time. We showed that sCTLA-4 from sera of patients with thyroid autoimmunity is able to bind its physiological ligands CD80/CD86 and displays functional activities on different in vitro systems (T-cell proliferation induced by specific soluble antigens, bi-directional mixed lymphocyte reaction). In conclusion, we demonstrate an increment of sCTLA-4 in serum of patients with autoimmune thyroid diseases. Its possible pathogenetic role during autoimmune processes can be speculated: sCTLA-4 can specifically inhibit the early T-cell activation by blocking the interaction of CD80/CD86 with the co-stimulatory receptor CD28. Conversely, higher levels of sCTLA-4 could compete with membrane-bound CTLA-4 for CD80/CD86, in later T lymphocytes activation phase, causing a reduction of inhibitory signaling.

CT60 genotype does not affect CTLA-4 isoform expression despite association to T1D and AITD in northern Sweden

BACKGROUND

Polymorphisms in and around the CTLA-4 gene have previously been associated to T1D and AITD in several populations. One such single nucleotide polymorphism (SNP), CT60, has been reported to affect the expression level ratio of the soluble (sCTLA-4) to full length CTLA-4 (flCTLA-4) isoforms. The aims of our study were to replicate the association previously published by Ueda et al. of polymorphisms in the CTLA-4 region to T1D and AITD and to determine whether the CT60 polymorphism affects the expression level ratio of sCTLA-4/flCTLA-4 in our population.

METHODS

Three SNPs were genotyped in 253 cases (104 AITD cases and 149 T1D cases) and 865 ethnically matched controls. Blood from 23 healthy individuals was used to quantify mRNA expression of CTLA-4 isoforms in CD4+ cells using real-time PCR. Serum from 102 cases and 59 healthy individuals was used to determine the level of sCTLA-4 protein.

RESULTS

Here we show association of the MH30, CT60 and JO31 polymorphisms to T1D and AITD in northern Sweden. We also observed a higher frequency of the CT60 disease susceptible allele in our controls compared to the British, Italian and Dutch populations, which might contribute to the high frequency of T1D in Sweden. In contrast to previously published findings, however, we were unable to find differences in the sCTLA-4/flCTLA-4 expression ratio based on the CT60 genotype in 23 healthy volunteers, also from northern Sweden. Analysis of sCTLA-4 protein levels in serum showed no correlation between sCTLA-4 protein levels and disease status or CT60 genotype.

CONCLUSION

Association was found between T1D/AITD and all three polymorphisms investigated. However, in contrast to previous investigations, sCTLA-4 RNA and protein expression levels did not differ based on CT60 genotype. Our results do not rule out the CT60 SNP as an important polymorphism in the development of T1D or AITD, but suggest that further investigations are necessary to elucidate the effect of the CTLA-4 region on the development of T1D and AITD.

The interleukin-10 inducing effect of transforming growth factor-beta on human naive CD4+ T cells from cord blood is restricted to the TH1 subset

Transforming growth factor (TGF-beta) seems to play a role in the regulation of immune responses, mainly by its suppressive function towards cells of the immune system. However, both in mice and human, conflicting data are published on the capacity of TGF-beta to induce interleukin (IL)-10 secretion in both naive and skewed T cell populations. Our aim was to test the IL-10-inducing capacity of TGF-beta in both naive and skewed cord blood mononuclear cells (CBMCs) and elucidate the mechanism by which TGF-beta exerts its effect. Therefore, naive CBMCs and CBMCs during skewing under T helper 1 (Th1) and Th2 polarizing conditions were stimulated with CD3 and/or CD28 in the presence or absence of TGF-beta. Proliferation, cytokine production and mRNA expression of transcription factors was measured. TGF-beta enhanced the IL-10 production in Th1 and naive cells only, and suppressed the T(H)1 phenotype as demonstrated in cytokine levels and T-box expression in T cells (T-bet) expression. Interestingly, forkhead box p3 (Foxp3) expression tended to increase in both Th1 and Th2 cells. These data indicate that TGF-beta can induce a regulatory phenotype in both naive and Th1-polarized cells derived from cord blood. The induction of IL-10 was not observed in Th2-polarized phenotype, indicating that TGF-beta might be especially of interest for immunomodulation in Th1 cells.

Differential regulation of IL-2 and IL-4 in patients with tobacco-related oral squamous cell carcinoma

AIM

The aim of the study was to investigate the systemic immunity in terms of major lymphocyte subsets and the expression of IL-2 and IL-4 in T-cell subsets from peripheral blood of patients with tobacco-related intraoral squamous cell carcinoma.

METHODS

CD3+, CD4+ and CD8+ T-cell subsets and CD16+ CD56+ natural killer cells, and intracellular cytokines in T-cell subsets were determined by two-colour flow cytometry and confocal microscopy.

RESULTS

Oral cancer patients showed a significantly reduced (P < 0.001) CD3+ and CD4+ T-cell subsets with a lower CD4/CD8 ratio when compared with the normal controls. The frequency of CD3+ IL-4+ and CD8+ IL-4+ T cells were significantly higher (P < 0.001) while CD4+ IL-2+ were significantly lower (P < 0.02) in patients when compared with the normal controls. Late stage of the tumour was associated with reduced expression of IL-2 in both CD4+ (P < 0.05) and CD8+ (P < 0.03) subsets.

CONCLUSIONS

The tobacco-related intraoral squamous cell carcinoma seems to be associated with multiple systemic immune defects particularly, an impaired CD3+ and CD4+ T cells in the peripheral blood as well as a differential regulation of IL-2 and IL-4 in CD4+ and CD8+ T-cell subsets. The cytokine response in these patients seems to be skewed from protective Th1 to immunosuppressive Th2 type. Thus these patients could be ideal candidate for immunomodulation therapy.

CTLA-4 gene polymorphisms and natural soluble CTLA-4 protein in psoriasis vulgaris

CTLA-4 molecule is an important inhibitor of T-lymphocyte activation. Several single nucleotide polymorphisms (SNPs) in the CTLA-4 gene were found, and their associations with many human diseases were described. So far, however, such studies have not been performed in psoriasis vulgaris in Caucasoids. Therefore, we examined the distribution of three CTLA-4 SNPs: -1147C/T, -318C/T and +49 A/G in 116 patients with psoriasis vulgaris and 123 healthy blood donors using the polymerase chain reaction-restriction fragment length polymorphism method. For all three SNPs, the frequencies of alleles, genotypes and three-point haplotypes were very similar in patients and controls, suggesting no contribution of these genetic variants to psoriasis.

Plasma concentrations of soluble CTLA-4, CD28, CD80 and CD86 costimulatory molecules reflect disease severity of acute asthma in children

Recent studies have demonstrated an elevation of plasma soluble costimulatory molecules B7.1 (CD80) and B7.2 (CD86), and their T lymphocyte counter receptors cytotoxic T lymphocyte associated antigen-4 (CTLA-4) and CD28 in asthmatic patients. We hypothesized that these costimulatory molecules may reflect the severity of asthma and investigated the longitudinal changes of these soluble costimulatory molecules, and their clinical significance in children with an asthmatic exacerbation. Sixteen children hospitalized for asthmatic exacerbation were recruited and treated with systemic corticosteroid (CS) for 5 days. Plasma total Immunoglobulin E (IgE) and eosinophil cationic protein (ECP) concentrations were measured by microparticle immunoassay and fluorescence enzyme immunoassay, respectively. Soluble CTLA-4 (sCTLA-4), sCD28, sCD80, and sCD86 concentrations in plasma were measured by enzyme-linked immunosorbent assay, and their relationships with asthma severity, total IgE, ECP concentrations, and blood eosinophil count were analyzed. Plasma sCTLA-4, sCD28, sCD80, and sCD86 concentrations in patients were highest during the acute attack. They decreased significantly with a parallel increase of peak expiratory flow rate (PEFR) after CS treatment (all P < 0.05). Plasma sCTLA-4, sCD28, and sCD86 concentrations of patients at recruitment were inversely correlated with PEFR, whereas plasma sCD28 and sCD86 concentrations correlated positively with eosinophil count and plasma ECP concentration (all P < 0.05). Although there was no such correlation with IgE concentration, sCD28 was correlated very significantly with eosinophil count (r = 0.83, P < 0.0001). In conclusion, plasma sCTLA-4, sCD28, sCD86, and sCD80 concentrations may reflect the severity of acute asthma and more studies on larger cohorts are needed to assess whether these markers are useful for assessing asthmatic exacerbation in children.

Flow cytometric assessment of hematopoietic cell subsets in cryopreserved preterm and term cord blood, influence of obstetrical parameters, and availability for transplantation

OBJECTIVE

The aim of this study was to characterize the lymphocyte and the hematopoietic stem and progenitor cell (HPC) subsets of cryopreserved premature cord blood (PCB) compared to term cord blood (TCB) by flow cytometry, to study the influence of birth conditions, and to assess its availability for transplantation.

MATERIALS AND METHODS

Four-color flow cytometric analysis was performed on 43 PCB and 40 TCB cryopreserved samples using a panel of 24 different mAbs, directed against lymphoid and HPC surface markers. The CB volume was estimated by the weight of the newborn to determine the absolute MNC and CD34(+) cell content/CB sample. Clinical and obstetrical data were recovered. Statistical comparisons and a multiple regression analysis were performed.

RESULTS

No consistent differences were found in the mononuclear cell (MNC) or CD34(+) cell concentration (x10(6)/L) between PCB and TCB. The percentage of primitive HPC (CD34(+)CD38(-), CD34(+)CD38(-)CD90(-)HLA-DR(-), CD34(+)CD38(-)CD90(-)HLA-DR(+)) and primitive lymphoid progenitors (CD34(+)CD7(+), CD34(+)CD7(+)CD19(-)CD117(-)) were higher in PCB than in TCB. Correspondingly, TCB had an increased percentage of committed HPC. No sample of PCB contained >2 x 10(7) MNC/kg (and only 48% had >1 x 10(5) CD34(+) cells) for a recipient of 20 kg body wt, as the minimum threshold recommended for CB transplantation. Obstetrical factors modulated mainly lymphocyte subsets and fewer HPC subpopulations. Acute fetal distress increased CD34(+) cells, especially the immature subsets. Maternal treatment with dexamethasone and intrauterine growth retardation decreased CD3(+) cells. No other obstetrical factors played a detrimental effect on CB cells if used for transplantation.

CONCLUSION

PCB is richer in immature cells both in lymphocyte and HPC populations, and its use for transplantation, at least in special cases, should be reconsidered.

Mucosal but not peripheral FOXP3+ regulatory T cells are highly increased in untreated HIV infection and normalize after suppressive HAART

Recent evidence indicates that regulatory T cells (T(regs)) play an important role in HIV infection. However, although the gastrointestinal mucosa is a key compartment in HIV disease, no data on mucosal T(regs) in HIV infection are available. In this study, we compared the frequency of T(regs) in duodenal mucosa and peripheral blood (PB) of 13 treatment-naive and 13 suppressively treated HIV-infected patients with that of 6 patients with norovirus infection and 12 healthy controls. T(regs) were quantified by immunohistochemistry (CD3/FOXP3) and further characterized (CD25, CTLA-4, GITR) by immunohistochemistry, immunofluorescence, and fluorescence-activated cell sorting (FACS). Both the frequency and the absolute count of mucosal T(regs) were highly increased in untreated HIV patients but were normal in treated HIV patients. In contrast, in peripheral blood of HIV patients, the absolute number of T(regs) was not increased, and their frequency was only slightly elevated. In norovirus infection, frequency of mucosal T(regs) in the CD4+ T-cell subset was not elevated. The high increase in count and frequency of mucosal T(regs) seems to be a characteristic feature of untreated HIV infection, suggesting a significant contribution of T(regs) to the pathogenesis of HIV disease. Their role may be 2-edged: attenuating HIV-induced immune hyperactivation while suppressing the immune response to HIV and mucosal pathogens.

Increased TGF-beta, Cbl-b and CTLA-4 levels and immunosuppression in association with chronic immune activation

In this study we investigated the mechanisms mediating T-cell hyporesponsiveness in chronically immune-activated individuals. We analyzed in healthy and persistently helminth-infected individuals the relationship between immune activation and general T-cell hyporesponsiveness, Th3/regulatory T-cell expression, transforming growth factor-beta (TGF-beta) secretion, CTL-associated antigen 4 (CTLA-4) levels, Casitas B-cell lymphoma-b (Cbl-b) (a negative regulator of T-cell activation) levels and phosphorylation of mitogen-activated protein kinases/extracellular signal-regulated kinase (ERK)-1 and -2. We found a very significant increase in plasma levels of TGF-beta and intracellular pools of CTLA-4 and Cbl-b in association with immune activation, which correlates with decreased T-cell responses to anti-CD3 stimulation. We demonstrate that the impaired activity of ERK of peripheral T cells in highly immune-activated individuals is associated with increased levels of CTLA-4 and Cbl-b. Interestingly, in some, but not in all, of these immune-activated individuals, induction of Cbl-b intracellular pools occurs by TGF-beta or CTLA-4 stimulation. We suggest that the higher levels of CTLA-4 and TGF-beta, both involved in the induction of Cbl-b, point at potential mechanisms underlying general and antigen-specific immune hyporesponsiveness in chronically infected individuals.

[Adenovirus-mediated CTLA4Ig and OX40Ig gene transfer induces long-term survival of cardiac allografts in rats]

OBJECTIVE

To investigate the potential role of CTLA4Ig gene and OX40Ig protein in inducing transplantation tolerance and the mechanisms thereof.

METHODS

Thirty Lewis rats underwent transplantation of the hearts of DA rats and then randomly divided into five equal groups: control group, blank virus AdEGFP treated group (adenovirus containing EGFP at the dose of 1-5 x 10(9) pfu/ml was infused via portal vein immediately after the operation), AdCTLA4Ig treated group, AdOX40Ig treated group, and AdCTLA4Ig-IRES-OX40Ig treated group. The cardiac allograft survival was monitored by daily palpation. The total cessation of beating was defined as rejection and was confirmed by histology. Peripheral venous blood samples were collected 0, 3, 7, 10, 14, 21 and 28 days after the administration of adenovirus. ELISA was used to detect the expression of CTLA4Ig and OX40Ig. Twenty days after the heart transplantation single splenocyte suspension was prepared from surviving Lewis rats to be used as responder. The spleens of the normal donor-DA rats and the third strain DA rats to prepare single cell suspension of the same density to perform mixed lymphocyte reaction (MLR). Then recombinant IL-2 was added into the mixed MLR system to observe t\if the MLR could be reversed. Twenty days after the heart transplantation the splenocytes of the tolerating Lewis rats were injected into the lingual vein of the normal Lewis rats to observe the delayed type hypersensitivity (DTH) of the transferred Lewis rat to normal rat splenocytes. RT-PCR was used to detect the mRNA expression of IL-2, interferon-gamma, IL-4, and IL-10.

RESULTS

The survival time of the AdCTLA4Ig-IRES-OX40Ig treated group was 151.5 d +/- 42.6 d, significantly longer than those of the AdOX40Ig treated group (60.2 d +/- 11.4 d (P = 0.003), AdCTLA4Ig (43.2 d +/- 11.1 d, P = 0.0026), control group (5.7 d +/- 0.5 d, P = 0.000 43), and AdEGFP treated group (5.2 d +/- 0.4 d, P = 0.000 43). CTLA4Ig and/or OX40Ig proteins were expressed at a high level in the adenoviral treated rats. Compared with the control group the splenocytes of the AdCTLA4Ig-IRES-OX40Ig, AdCTLA4Ig, and AdOX40Ig treated groups displayed donor-specific hyporesponsiveness (P = 0.0016, 0.0026 and 0.001), which could be partly reversed by the addition of exogenous IL-2. Moreover, the hyporesponsiveness could be transferred to the same strain rats through adoptive transfer. In comparison with the normal controls, the expression of Th1 type cytokines, such as IL-2 and IFN-gamma, was significantly decreased in the tolerating rats and significantly increased in the rats with rejection; however the expression of the Th2 type cytokines, such as IL03 and IL-10, was significantly increased in the tolerating rats and significantly decreased in the rats with rejection, showing a deviation of Th1/Th2 type cytokines.

CONCLUSION

AdCTLA4Ig-IRES-OX40Ig-mediated genes transfer renders prolonged expression of CTLA4Ig and OX40Ig in Lewis recipient rats, leading to a long-term survival of cardiac allografts. The induced tolerance is donor-specific, and the mechanisms may be associated with T cell anergy, deviation of Th1/Th2, and the regulatory T cells.

[Relationship of CTLA-4 exon 1 A49-->G polymorphism with sCTLA-4 and Th1/Th2 bias in idiopathic dilated cardiomyopathy]

OBJECTIVE

To investigate the association of cytotoxic T lymphocyte associated antigen-4 (CTLA-4) gene exon 1 A49-->G polymorphism with the genetic susceptibility to idiopathic dilated cardiomyopathy (IDC) in Chinese Han nationality.

METHODS

Peripheral blood samples were collected from 48 patients with IDC, 31 males and 17 females, and 50 sex- and age-matched normal controls. ELISA was used to examine the cytokines: sCTLA-4, gamma-interferon (IFN-gamma), and interleukin-4 (IL-4)with the ratio of IFN-gamma/IL-4 as an indicator for Th1/Th2 bias. PCR-RFLP was used to analyze the A/G polymorphism of CTLA-4 exon 1 A49-->G. The relationship of CTLA-4 genotype and alleles frequencies with sCTLA-4, IFN-gamma and IFN-gamma/IL-4 was evaluated by linear regression analysis.

RESULTS

Compared with the normal controls, the frequencies of GG genotype (0.6042 and 0.7396, P = 0.012) and the G allele (0.36 and 0.56, P = 0.008) were significantly increased in the patients with IDC. Increased serum sCTLA-4 was found in the IDC group compared with the controls (1.87 microg/L +/- 1.06 microg/L vs. 0.54 microg/L +/- 0.19 microg/L, P < 0.05). IFN-gamma was significantly lower in the IDC group than in the control group (16 ng/L +/- 6 ng/L vs. 30 ng/L +/- 10 ng/L, P < 0.05). The ratio of IFN-gamma/IL-4 was significantly in the IDC group than in the control group (1.63 +/- 0.50 vs. 3.01 +/- 0.89, P < 0.05). No statistically difference was found in the IL-4 level between the two groups. Linear regression analysis manifested significant interrelationship between the GG genotype, G allele frequencies and serum sCTLA-4 (r = 0.57, P = 0.021), IFN-gamma/IL-4 ratio (r = 0.42, P = 0.028) in the IDC group. While no correlation was found for AA, AG genotype and the A allele frequency.

CONCLUSION

CTLA-4 gene exon 1 A49-->G substitution is associated with an increased IDC genetic susceptibility, which implicates that the CTLA-4 gene may have a significant role in IDC, possibly via a Thr-->Ala change in CTLA-4 signal peptide, with a result of functional change of sCTLA-4. The bias of Th1/Th2 paradigm is associated with the increased sCTLA-4 level under certain background of immunogenicity.

Increased expression of plasma and cell surface co-stimulatory molecules CTLA-4, CD28 and CD86 in adult patients with allergic asthma

The co-stimulatory interactions of the B7 family molecules CD80 and CD86 on antigen-presenting cells, together with their T cell counter receptors CD28 and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), modulate T lymphocyte-mediated immune responses in a reciprocal manner. To investigate whether there is altered expression and the clinical significance of soluble co-stimulatory molecules in asthmatic patients, plasma concentrations of sCTLA-4, sCD28, sCD80 and sCD86 in 51 adult allergic asthmatic adults with or without steroid treatment, and 35 sex- and age-matched control subjects were measured by enzyme-linked immunosorbent assay (ELISA). Cell surface expression of CTLA-4 and CD28 on peripheral blood mononuclear cells (PBMC) were analysed by flow cytometry. Results showed that the plasma sCTLA-4 concentration was significantly higher in all asthmatic patients while sCD28 and sCD86 concentrations were significantly higher in steroid and non-steroid treated asthmatic patients, respectively, compared with control subjects (all P < 0.01). Significantly increased cell surface expression of CD28 but not CTLA-4 on PBMC was found in asthmatic patients compared with controls (P < 0.05). The plasma concentration and cell surface expression of CTLA-4 were found to exhibit positive and significant correlations with those of CD28 (both P < 0.05). Serum total IgE concentration correlated positively and significantly with sCTLA-4 and sCD28 concentrations in allergic asthmatic patients (both P < 0.05). The increased expression of these soluble co-stimulatory molecules may reflect the dysregulation of T cell activation, thereby contributing to the immunopathogenesis of allergic asthma.

Effects of allergen inhalation and oral glucocorticoid on serum soluble CTLA-4 in allergic asthmatics

BACKGROUND

The serum soluble cytotoxic T lymphocyte associated antigen-4 (sCTLA-4) concentration is significantly elevated in patients with asthma, and sCTLA-4 concentration correlate with the severity of asthma. The aim of the present study was to investigate effects of allergen inhalation and oral glucocorticoid on concentration of serum sCTLA-4 in patients with allergic asthma.

METHODS

Allergen inhalation challenge was conducted in allergic asthmatics with isolated early asthma response and those with dual asthma response. In a randomized, double-blind, placebo-controlled, parallel group fashion, prednisolone or placebo was give orally once a day for 2 weeks. Venous blood samples were collected before and after allergen inhalation or prednisolone administration for obtaining sera. The serum sCTLA-4 concentrations were determined using enzyme-linked immunosorbent assay.

RESULTS

The serum sCTLA-4 concentrations in the dual responder group increased from 29.0 (14.5-43.7) microg/l [median (25-75 percentiles)] before allergen inhalation to 44.0 (24.3-61.3) microg/l 24 h after allergen inhalation. In the isolated early responders, there were no significant increase in serum sCTLA-4 concentrations after allergen inhalation compared with baseline levels. There was a significant decrease in serum sCTLA-4 concentrations after 2 weeks of glucocorticoid therapy [22.0 (15.5-31.0) microg/l] compared with baseline values [37.0 (19.5-53.0) microg/l], whereas there was no significant difference in the placebo group.

CONCLUSION

This study has demonstrated that serum sCTLA-4 concentrations increased after allergen inhalation in sensitized asthmatic subjects, and that serum sCTLA-4 concentrations were downregulated by prednisolone therapy.

Aberrant production of soluble costimulatory molecules CTLA-4, CD28, CD80 and CD86 in patients with systemic lupus erythematosus

OBJECTIVE

The costimulatory interactions of the B7 family molecules CD80 and CD86 on antigen-presenting cells with their T-cell counter-receptors CD28 and CTLA-4 modulate T lymphocyte-mediated immune responses in a reciprocal manner. We investigated the possible aberrant production of soluble (s) forms of the T-cell costimulatory molecules CD80, CD86, CD28 and CTLA-4 in plasma of patients with systemic lupus erythematosus (SLE), an autoimmune disease arising from T-lymphocyte dysregulation.

METHODS

Plasma concentration and ex vivo production of soluble costimulatory molecules of 79 SLE patients with or without active disease and 40 sex- and age-matched healthy subjects were measured by enzyme-linked immunosorbent assay.

RESULTS

Plasma sCTLA-4, sCD28, sCD80 and sCD86 concentrations of all SLE patients were significantly higher than concentrations in control subjects (all P<0.01). These increases were observed even in patients with inactive disease [SLE Disease Activity Index (SLEDAI) <3]. Plasma sCTLA-4 concentration in all SLE patients correlated significantly with SLEDAI score (r = 0.228, P = 0.043). Upon mitogen treatment of peripheral blood mononuclear cells, the percentage increases in ex vivo production of sCD28 and sCD80 and the percentage decrease in sCTLA-4 release were all significantly smaller in SLE patients with active disease than in healthy subjects (P<0.01, P<0.05 and P<0.0001, respectively).

CONCLUSION

The aberrant production of soluble T-cell costimulatory molecules is important in the immunopathogenesis of SLE, which occurs by the dysregulation of T-lymphocyte costimulation. Plasma sCTLA concentration could potentially serve as a surrogate marker of SLE disease activity.

Elevation of plasma soluble T cell costimulatory molecules CTLA-4, CD28 and CD80 in children with allergic asthma

BACKGROUND

The surface expression of T cell costimulatory molecules CTLA-4 and CD28 and their counter-ligands, B7 molecules (CD80, CD86), is differentially induced for T cell activation and expansion in allergic asthma. However, the role of their soluble forms in plasma has not yet been elucidated. In this study, we investigated whether expression is altered and whether soluble costimulatory molecules are clinically relevant in asthmatic patients.

METHODS

Plasma concentrations of soluble CTLA-4 (sCTLA-4), CD28, CD80 and CD86 in 51 children with chronic allergic asthma with or without inhaled corticosteroid treatment, and 22 sex- and age-matched control subjects were measured by enzyme-linked immunosorbent assay. Plasma total IgE concentration was measured using a microparticle immunoassay.

RESULTS

Asthmatic patients had higher logarithmic plasma total IgE concentration (IgE(log)) than healthy subjects (p < 0.0001). In non-steroid-treated patients, plasma sCTLA-4, sCD28 and sCD80 but not sCD86 concentrations were significantly higher than those of control subjects (all p < 0.05). Plasma sCD80 and sCD86 but not sCTLA-4 and sCD28 concentrations correlated significantly with IgE(log) of all subjects (p < 0.05). There were also significant positive correlations between sCTLA-4 and sCD28 (p = 0.0007), and between sCD80 and sCD86 in all asthmatic patients (p = 0.001).

CONCLUSIONS

Plasma sCTLA-4, sCD28 and sCD80 concentrations are elevated in allergic asthma. The increased expression of these soluble proteins may reflect the dysregulation of T cell activation, contributing to the immunopathogenesis of allergic asthma.

Soluble CTLA-4 in sera of patients with bronchial asthma

Cytotoxic lymphocyte associated antigen-4 (CTLA-4) is a homologue of CD28, which plays a critical role in the down-regulation of antigen-activated immune response. The aim of the present study was to investigate the concentrations of soluble CTLA-4 in sera of patients with bronchial asthma and the correlation between soluble CTLA-4 concentrations and some clinical measures of asthma. The concentrations of serum soluble CTLA-4 in 31 atopic asthmatics, 20 non-atopic asthmatics, and 28 non-atopic normal control volunteers were determined by ELISA technique, and the relationship between serum soluble CTLA-4 concentrations in asthmatics and airway responsiveness, pulmonary function, blood white cell counts and differentials, respectively, were analyzed. Serum soluble CTLA-4 concentrations in both atopic asthmatics (20.2 +/- 5.4 microg/L) and non-atopic asthmatics (19.2 +/- 6.2 microg/L) were all higher than that in normal controls (1.8 +/- 0.8 microg/L, p = 0.04 and 0.014, respectively). There was no difference in serum soluble CTLA-4 concentrations between atopic and non-atopic asthmatics (p = 0.877). The serum soluble CTLA-4 concentrations in the asthmatics statistically correlated with forced expiratory volume in one second (r = -0.410, p = 0.027), percentage of predicted peak expiratory flow (r = -0.449, p = 0.015), and PaCO2 (r = 0.555, p = 0.002), respectively. Our data also showed that the concentration of soluble CTLA-4 was significantly related to blood lymphocyte numbers. The serum soluble CTLA-4 protein level was significantly elevated in patients with asthma. This level correlated with the severity of asthma. Our data also showed that the concentration of soluble CTLA-4 was significantly related to blood lymphocyte numbers.

[Studies on the genetic pathogenesis of myasthenia gravis caused by CTLA-4 gene polymorphism]

OBJECTIVE

To study the genetic pathogenesis of myasthenia gravis (MG) caused by cytotoxic T lymphocyte associated antigen-4 (CTLA-4) gene polymorphisms and regulation function of transcription factor.

METHODS

ELISA assay was used to determine the expression level of serum sCTLA-4 in MG. Four single nucleotide polymorphisms (SNPs) of CTLA-4 at exon 1 +49, promoter -318, -1661, -1772 were analyzed by restriction fragment length polymorphism (RFLP). Transcription factor nuclear factor 1(NF-1) and c/EBPbeta binding site were confirmed by chromatin immunoprecipitation(CHIP) assay.

RESULTS

It was found that the frequencies of the GG+49 genotype and G+49 allele are higher in MG patients with thymoma than those in patients of thymic hyperplasia and normal thymus subgroups. T/C-318 is not correlated with MG. The frequency of CT-1772 genotype is significantly higher in MG patients, especially in MG patients with thymoma, when compared with that in healthy controls. Meanwhile, the frequency of the G-1661 allele and GG-1661 genotype is lower in MG patients. Linkage disequilibrium (LD) between each SNPs in promoter -1772, -1661, -318 and coding sequence 1 (CDS 1) +49 is apparent. sCTLA-4 levels in patients' sera are correlated with the haplotype and genotype. T/C-1772 and A/G-1661 SNPs change the sequence of transcription factor NF-1 and c/EBPbeta binding sites. DNA variants lose site-specific binding activity of transcription factor regulated by lectin ConA and PHA.

CONCLUSION

There are strong positive linkages among four SNPs. C/T-1772 and A/G-1661 polymorphisms can result in inefficient transcription of CTLA-4 gene. T>C-1772 mutation also affects gene splicing. These SNPs may constitute a factor of susceptibility to disease.

Gender-limited association of cytotoxic T-lymphocyte antigen-4 (CTLA-4) polymorphism with cord blood IgE levels

Allergic mechanism has long been attributed to IgE-mediated reaction. The relationship between gene polymorphism and cord blood IgE (CB IgE) is unclear. We investigated whether elevation of CB IgE levels was associated with polymorphisms of cytotoxic T-lymphocyte antigen 4 (CTLA-4) at (-318) CT and (+49) AG positions in a gender-limited fashion. CB IgE levels were determined by Pharmacia CAP system and the CTLA-4 polymorphisms at (-318) and (+49) were determined by restriction fragment length polymorphism (RFLP). A total of 644 consecutive umbilical cord bloods were collected for this study. 32.9% of newborn infants had detectable IgE levels (> or =0.35 kU/l). 25.6% of the male newborns had elevated CB IgE levels (> or =0.5 kU/l) similar to those of the female newborns (22.7%). The CTLA-4 polymorphism at (+49) but not (-318) was significantly associated with elevated CB IgE levels (p = 0.004). The association of CTLA-4 (+49) A allele with elevated CB IgE levels was found only in females. Both male and female infants with different CTLA-4 (-318) genotypes had no difference in the rates of elevated CB IgE levels. A linkage disequilibrium between CTLA-4 (+49) G and (-318) C allele was found in this Chinese population. Subjects with the (+49, GG and -318, CC) genotype had a significantly lower rate of elevated CB IgE levels. Association of the CTLA-4 (+49) polymorphism with elevated CB IgE levels was found only in female infants. Newborn infants with the (+49, GG and -318, CC) genotype tended to have a low rate of elevated CB IgE.

Expression of CTLA-4 (CD152) in peripheral blood T cells of children with influenza virus infection including encephalopathy in comparison with respiratory syncytial virus infection

Influenza virus and respiratory syncytial virus (RSV) are the most common causes of acute severe respiratory infection in children during the winter. There have been few reports about peripheral blood T cell activation in vivo in influenza virus infection and conflicting results concerning peripheral blood T cells activation in RSV infection. Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4, CD152) is a receptor present on T cells that plays a critical role in the down-regulation of antigen-activated immune responses. To clarify the status of peripheral blood T cells, we investigated intracellular CTLA-4 expression in T cells in patients with influenza virus and RSV infection. We collected blood samples from 15 patients with influenza virus infection, including three with complications of influenza virus-associated encephalopathy and 18 patients with RSV infection, as well as 44 healthy children. We determined the intracellular expression of CTLA-4 in CD4+ and CD8+ T cells by flow cytometry. There were no significant differences in the percentages of intracellular CTLA-4-positive CD4+ T cells and CD8+ T cells by age. The percentages of intracellular CTLA-4-positive CD4+ T cells in the patients with influenza virus infection were significantly higher than those in healthy children (P < 0.01). In particular, the patients with influenza virus-associated encephalopathy had sevenfold higher percentages of CTLA-4-positive CD4+ T cells than influenza patients without encephalopathy (P < 0.05). The patients with influenza virus-associated encephalopathy had increased percentages of CTLA-4-positive CD8+ cells at the acute stage in comparison with the convalescent stage and in control subjects (P < 0.01, respectively). RSV patients showed no increase in CTLA-4-positive CD4+ T cells or CD8+ T cells. The immunological status of peripheral T cell activation is substantially different in influenza virus infection and RSV infection. The patients with RSV infection did not show any increase in CTLA-4-positive peripheral blood T cells. There was a remarkable increase in intracellular CTLA-4 in CD4+ and CD8+ T cells in influenza virus-associated encephalopathy. Down-regulation of antigen-activated peripheral blood T cell activation might play an important role in the pathogenesis of influenza virus-associated encephalopathy and host defence against influenza virus infection.

Biological function of the soluble CEACAM1 protein and implications in TAP2-deficient patients

Interactions of natural killer (NK) cells with MHC class I proteins provide the main inhibitory signals controlling NK killing activity. It is therefore surprising to learn that TAP2-deficient patients suffer from autoimmune manifestations only occasionally in later stages of life. We have previously described that the CEACAM1-mediated inhibitory mechanism of NK cytotoxicity plays a major role in controlling NK autoreactivity in three newly identified TAP2-deficient siblings. This novel mechanism probably compensates for the lack of MHC class I-mediated inhibition. The CEACAM1 protein can also be present in a soluble form and the biological function of the soluble form of CEACAM1 with regard to NK cells has not been investigated. Here we show that the homophilic CEACAM1 interactions are abrogated in the presence of soluble CEACAM1 protein in a dose-dependent manner. Importantly, the amounts of soluble CEACAM1 protein detected in sera derived from the TAP2-deficient patients were dramatically reduced as compared to healthy controls. This dramatic reduction does not depend on the membrane-bound metalloproteinase activity. Thus, the expression of CEACAM1 and the absence of soluble CEACAM1 observed in the TAP2-deficient patients practically maximize the inhibitory effect and probably help to minimize autoimmunity in these patients.

Serum soluble CTLA-4 levels are increased in diffuse cutaneous systemic sclerosis

OBJECTIVE

To determine serum levels of soluble cytotoxic T-lymphocyte associated molecule-4 (sCTLA-4) and clinical association in patients with systemic sclerosis (SSc).

METHODS

Serum sCTLA-4 levels from 32 patients with diffuse cutaneous SSc (dSSc) and 27 patients with limited cutaneous SSc (lSSc) were examined by enzyme-linked immunosorbent assay (ELISA). For a longitudinal study, 211 sera from 30 SSc patients were analysed (follow-up 2.1-7.0 yr).

RESULTS

Serum sCTLA-4 levels were elevated in dSSc patients compared with normal controls (n = 41), lSSc patients and patients with active systemic lupus erythematosus (SLE) (n = 23). By contrast, sCTLA-4 levels in patients with lSSc or SLE were normal. SSc patients with elevated sCTLA-4 levels had a shorter disease duration and more frequent presence of digital pitting scars, contracture of phalanges, diffuse pigmentation, pulmonary fibrosis and decreased percentage vital capacity (%VC) than those with normal sCTLA-4 levels. sCTLA-4 levels correlated positively with the extent of skin fibrosis, serum IgG levels and anti-topoisomerase I antibody levels. In a longitudinal study, sCTLA-4 levels decreased on a parallel with improvement of skin sclerosis in five dSSc patients. Skin sclerosis did not improve in two of six dSSc patients with high sCTLA-4 levels throughout the follow-up, while the remaining four patients showed improvement of skin sclerosis.

CONCLUSION

These results suggest that sCTLA-4 correlates with disease severity and activity of SSc and that sCTLA-4 plays a role in immunological abnormalities of SSc, since sCTLA-4 may augment humoral immune responses as well as T-cell responses by interfering with B7-CTLA-4 interactions that induce negative signals in T and B cells.

Polymorphism of the immune-braking gene CTLA-4 (+49) involved in gender discrepancy of serum total IgE levels and allergic diseases

BACKGROUND

A variety of genes are related to allergic disorders in different ethnic populations. The genetic basis for the gender discrepancy of allergic diseases remains to be determined.

OBJECTIVE

This study was conducted to investigate whether IL-4 promoter (-590 C/T) and cytotoxic T lymphocyte antigen 4 (CTLA-4) (+49 A/G) polymorphisms were correlated with a gender discrepancy of total IgE levels and allergic diseases in a Chinese population.

METHODS

A total of 1333 participants aged 19-49 years were enrolled in this study. Allergic diseases were recognized by the presence of asthma, rhinitis or atopic dermatitis in conjunction with detectable specific IgE in the blood. Polymorphisms of IL-4 promoter (-590) and CTLA-4 (+49) were determined by restriction fragment length polymorphism.

RESULTS

Males or females with allergic diseases had higher total IgE levels than those without (P=0.000). Females with the A/A genotype in the CTLA-4 (+49) position had significantly higher total IgE levels than those with A/G, and those with the G/G genotype had the lowest IgE levels (154.9 vs. 107.1 vs. 79.8 KU/L; mean log values: 1.79 vs. 1.65 vs. 1.54, P< 0.001). However, males with different genotypes in the CTLA-4 (+49) position exhibited no difference in the total IgE levels. Females with allergic rhinitis had a significantly higher frequency of the A/A genotype in the CTLA-4 (+49) polymorphism than those without atopic diseases (P=0.016). In contrast, males with and without allergic disorders exhibited no significant difference in the CTLA-4 (+49) polymorphisms (P>0.05). The IL-4 promoter (-590) polymorphisms, however, had no correlation with the total IgE levels or allergic diseases in either females or males.

CONCLUSION

In females only, the CTLA-4 (+49), but not the IL-4 promoter (-590), polymorphism was significantly associated with elevation of total IgE levels and allergic rhinitis. Here, we have, for the first time, demonstrated a gender-linked genetic relationship with allergic disease.

CD4 T cell activation and disease activity at onset of multiple sclerosis

We studied CD4 T cell activation in patients with clinically isolated syndromes (CIS) suggesting an initial attack of multiple sclerosis. The percentage of blood CD26+ CD4 T cells was increased in these patients, and correlated with magnetic resonance imaging disease activity and clinical disease severity. In contrast, the percentage of CD25+ CD4 T cells in cerebrospinal fluid correlated negatively with the cerebrospinal fluid concentration of myelin basic protein and the presence of IgG oligoclonal bands. These results suggest that distinct systemic and intrathecal T cell activation states correlate with disease activity and risk of subsequently developing MS in CIS patients.

[Surface expression of costimulatory molecules CD28/CTLA-4 on peripheral blood T lymphocytes in the course of type 1 diabetes mellitus in children and adolescents]

BACKGROUND

Type 1 diabetes is mediated by autoreactive - T lymphocytes recognizing pancreatic islet cell antigens. CD28/CTLA-4 costimulatory molecules participate in the transduction of the necessary signal in T lymphocytes proliferation and play an important role in the development of autoimmunological process.

OBJECTIVES

The purpose of this study was: to evaluate whether the expression of CD28, CTLA-4 molecules on peripheral blood T lymphocytes alters in the course of disease -- diabetes lasting less than 5 years and over 5 years; to assess a relationship between the percentage of CD28, CTLA-4 on T cells and the evolution of vascular complications (microalbuminuria, arterial hypertension, diabetic retinopathy).

MATERIAL AND METHODS

The study was carried out in three groups of subjects - 60 children (aged 9-20) with diagnosed type 1 diabetes: (a) (20 n) with the disease lasting >5 years, (b) (20 n) with type 1 diabetes lasting >5 years without vascular complications, (c) (20 n) with type 1 diabetes and vascular complications (microalbuminuria, arterial hypertension, diabetic retinopathy). The control group consisted of 20 healthy volunteers (aged 6-17). The expression of adhesion molecules has been evaluated by using three-color flow cytometry (Coulter EPICS XL). HbA1c concentration has been analysed by liquid chromatography technique HPLC-Variant (Bio-Rad).

RESULTS

In the study, the superficial expression of CTLA-4 receptor on T lymphocytes was enhanced in children with diabetes lasting <5 years (p<0.005) and over 5 years without vascular complications (p<0.01) versus healthy patients and tend to normalize in the presence of developing vascular complications In contrast, the expression of costimulatory molecule CD28 was decreased in children with type 1 diabetes lasting <5 years (p<0.05) as well as in children with developing vascular complications (p<0.01) versus the control group.

[Analysis of costimulatory molecules (CD28-CTLA-4/B7) expression on chosen mononuclear cells in adolescents with Graves' disease during methimazole therapy]

CD28 and CTLA-4 are glycoprotein molecules providing the potent costimulatory signal for T cells activation and proliferation via interactions with their ligands B7/BB1 molecule, present on the surface of Ag-presenting cells (APC). The present study was performed to elucidate the relationship between CTLA-4/CD28 molecules and stimulating (TSAb) or blocking (TBAb) antibodies to the TSH-receptor in Graves' disease. The aim of the study was to estimate the expression of CTLA-4 (cytolitic T lymphocyte associated antigen-4, CD152), CD28, B7.1 (CD80) and CD7.2 (CD86) molecules on peripheral blood cells in patients with Graves' disease (GD) (n=28, mean age 15.4), in patients with nontoxic nodular goiter (NTNG) (n=28, mean age 15.6 years) in comparison with sex- and age-matched healthy control subjects (n=28, mean age 15.9 years). The expression of the costimulatory molecules on mononuclear cells was analyzed by the three-color flow cytometry using a Coulter EPICS XL cytometer. Detection of stimulating and blocking antibodies to the TSH-receptor using JPO9 CHO cells in unfractionated serum was measured by a highly sensitive commercial radioimmunoassay. In untreated Graves' patients we observed a significant increase of CD152+ (p<0.004, p<0.004, p<0.001) and CD28+ (p<0.02, p<0.02, p<0.02) T lymphocytes in comparison to the non-toxic nodular goiter patients, healthy control subjects and euthyroid Graves' patients. After 2-6 months of methimazole therapy, the percentages of these cells in the peripheral blood of hyperthyroid patients returned to normal values. The analysis of CD3+ T lymphocytes co-expressing CD152 and CD28 antigens on peripheral blood revealed increased percentages of CTLA-4/CD28 positive cells in patients with Graves' disease (p<0.004, p<0.04) compared to the controls and euthyroid Graves' patients, while B7.1 (CD80) and B7.2 (CD86) molecules were detected only in some hyperthyroid patients on activated monocytes. In addition, 75% of children with untreated hyperthyroidism had positive TSAbs, whereas TBAbs were measured in 3 out of 7 TSAb negative patients with Graves' disease. In untreated Graves' patients a correlation between percentage of CD152+ T cells and serum level of stimulating and blocking antibodies to the TSH-receptor was found, while no such correlation was detected in relation to CD28+ T cells. We conclude that the changes of the expression of costimulatory molecules on peripheral blood mononuclear cells could be an important marker of activity of an autoimmune process in children and adolescents with Graves' disease and that their levels are modulated by thyroestatic treatment.

Assessment of selected adhesion molecules and lymphocyte subpopulations in children with IgA nephropathy

PURPOSE

The aim of the study was to assess the expression of selected adhesion molecules on mononuclear cells of peripheral blood and lymphocyte subpopulations in children with IgA nephropathy (IgAN).

MATERIAL AND METHODS

14 children with IgAN and 20 healthy controls were included in the study. Flow cytometry was used to determine the expression of such adhesion molecules as L selectin (CD62L), VLA-4 integrin (CD49d), intracellular molecule ICAM-1 (CD54) and cytotoxic lymphocyte molecule CTLA-4 (CD152), as well as the lymphocyte antigens: CD3, CD4, CD8, CD19, CD1656 (NK), CD4 and CD8 RO+ and RA+.

RESULTS

The findings revealed that the expression of the adhesion molecules VLA-4 and CTLA-4 did not differ from that of the healthy controls (p > 0.05). However, the expression of CD62L (L-selectin) was increased (p < 0.05). The expression of ICAM-1 was reduced, but not significantly, compared to the control group (p > 0.05). We found a decrease in the expression of NK cells (CD1656) and CD4/CD8 ratio, and an increase in CD8 cells (p < 0.05). In the group of 9/14 children, with proteinuria over 1.0 g/24 hours, a decreased expression of CD4 was additionally found (p < 0.05).

CONCLUSIONS

The children with IgAN show: 1. Changes in peripheral lymphocyte subpopulations involving an increase in CD8 cells and a decrease in CD1656(NK) cells, a reduction in the CD4/CD8 ratio, and additionally in cases with proteinuria a reduction in CD4 cell count, 2. Increased expression of L-selectin (CD62L) on peripheral blood mononuclear cells.

Marked elevation of human circulating CD4+CD25+ regulatory T cells in sepsis-induced immunoparalysis

OBJECTIVE

Immunoparalysis has recently emerged as a possible cause explaining the failure of clinical trials in septic shock. Because human peripheral blood CD4+CD25+ T cells have been characterized as suppressor T cells, we hypothesized they might be increased in sepsis-induced immunoparalysis.

DESIGN

Prospective, observational, clinical study.

SETTING

Adult intensive care units in a university hospital.

SUBJECTS

Patients with septic shock (n = 16) and healthy individuals (n = 36).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

In patients with septic shock (mortality rate at 28 days, 56%; mean admission Simplified Acute Physiology Score II, 47), we first illustrated immunoparalysis by showing a severe diminished monocytic human leukocyte antigen (HLA)-DR expression. Afterward, compared with control values, we found in these patients a marked elevation of circulating CD4+CD25+ T cells that were also CD45RO+ and CD69- and overexpressed CTLA-4. Importantly, nonsurvivors (n = 9) presented prolonged lower monocytic HLA-DR expression and higher percentage of CD4+CD25+ T-suppressor T cells.

CONCLUSIONS

These data support the concept that the persistence of a pronounced immunoparalysis after septic shock is associated with a poor outcome. Whether CD4+CD25+ T cells directly participate in sepsis-induced immunoparalysis remains to be investigated.

Increased expression of soluble cytotoxic T-lymphocyte-associated antigen-4 molecule in patients with systemic lupus erythematosus

A soluble form of cytotoxic T-lymphocyte-associated antigen-4 (sCTLA-4) was recently found and shown to possess a downregulatory function as a membrane-bound CTLA-4 molecule. The purpose of the study was to investigate the expression of sCTLA-4 molecule in patients with systemic lupus erythematosus (SLE). One hundred patients with SLE and 40 age- and sex-matched healthy individuals were enrolled in the study. The results showed that patients with SLE have significantly higher levels of sCTLA-4 in sera than healthy controls (21.6 +/- 12.3 ng/ml versus 5.9 +/- 5.4 ng/ml, P < 0.001). Increased expression of sCTLA-4 mRNA in peripheral blood mononuclear cells (PBMCs) was also found in SLE patients. However, we could not find a statistically significant correlation between the serum levels of sCTLA-4 and lupus disease activities. The reported CTLA-4 gene polymorphism in promoter region at position -318 did not affect the levels of sCTLA-4. To the best of our knowledge, this is the first report showing that patients with SLE have increased sCTLA-4 expression. However, the mechanism and role of increased sCTLA-4 in the pathogenesis of SLE remains elucidated.

High GAD65 autoantibody levels in nondiabetic adults are associated with HLA but not with CTLA-4 or INS VNTR

OBJECTIVES

To explore the relationship between genetic background and antibody levels in a nondiabetic population. We evaluated if high levels of autoantibodies against the 65 kDa isoform of glutamic acid decarboxylase (GAD65Ab), were associated with high-risk genes, i.e. HLA, CTLA-4 and INS VNTR genes.

DESIGN AND SUBJECTS

Seventy-five (M/F 39/36) subjects exceeding the 95th percentile of GAD65 autoantibody index and 75 age and sex matched subjects below the 95th percentile, randomly selected amongst participants in the Västerbotten Intervention Programme.

METHODS

The GAD65 Ab were measured in a radioligand-binding assay. HLA class II typing was performed by an oligoblot hybridization method. CTLA-4 repeat length was analysed and divided into short forms and long forms. Class I and class III alleles of INS VNTR were detected. Differences in distribution were tested by Pearson chi-square with Yates correction. Odds ratios (OR) were used to compare groups calculated with Cochran's and Mantel-Haenszel statistics.

RESULTS

The DQB1*0201-DQA1*0501-DRB1*03 haplotype was increased in subjects with high GAD65Ab levels (P = 0.04). This increase seemed to be explained by a difference in haplotype frequencies amongst men (P = 0.01). Calculating OR showed a significant association between the DQB1*0201-DQA1*0501-DRB1*03 haplotype and elevated levels of GAD65Ab in all subjects (OR 2.2, 95% CI 1.02-4.9) as well as in men (OR 4.6, 95% CI 1.3-15.9). There was no association between high levels of GAD65Ab and either INS VNTR or CTLA-4 polymorphisms.

CONCLUSION

Our study suggests that adult males with the DQB1*0201-DQA1*0501-DRB1*03 haplotype tend to develop high GAD65Ab titres. As none of these subjects have developed diabetes these data suggest that HLA may be important in GAD65Ab formation but that additional factors are required for the progression to overt type 1 diabetes.

Plasmacytoid dendritic cells: from specific surface markers to specific cellular functions

We have recently described a panel of monoclonal antibodies (mAb), that recognize two novel leukocyte surface antigens, BDCA-2 and BDCA-4. BDCA-2 is a novel type II C-type lectin specifically expressed by plasmacytoid dendritic cells (PDCs) that can internalize antigen for presentation to T cells. Furthermore, signaling via BDCA-2 may play a role in switching from interferon (IFN)-alpha/beta-controlled to interleukin (IL)-12-controlled immune response pathways, as triggering of BDCA-2 potently inhibits secretion of IFN-alpha/beta by PDCs and thereby promotes IL-12 p70 production in PDCs and other cells. Viruses may exploit this switch to escape innate antiviral immunity, but it may be beneficial for patients with systemic lupus erythematosus (SLE) if induced, for instance by anti BDCA-2 mAb treatment. BDCA-4 is shown here to be identical to neuropilin-1 (NP-1), a neuronal receptor for the axon guidance factors belonging to the class-3 semaphorin subfamily, and a receptor on endothelial and tumor cells for vascular endothelial growth factor (VEGF-A). In blood and bone marrow, BDCA-4/NP-1 is exclusively expressed on PDCs, but in tonsils also on a few other cells, primarily follicular B helper memory T cells (T(FH)).

CTLA4 gene polymorphisms in Dutch and Chinese patients with inflammatory bowel disease

BACKGROUND

Inflammatory bowel diseases (IBDs) are characterized by chronic intestinal inflammation as a result of an exaggerated T-cell response. CTLA4, a receptor of activated T cells, has an inhibitory function in regulating T-cell activation. Since CTLA4 gene polymorphisms have been associated with several autoimmune diseases, the aim was to study these gene polymorphisms in patients with IBD in two different populations.

METHODS

The C-318T polymorphism in the promoter region and A+49G polymorphism in exon I of the CTLA4 gene were investigated by a PCR-SSP method. We studied 139 unrelated patients with ulcerative colitis (UC), 163 patients with Crohn disease (CD) and 174 healthy controls of Dutch Caucasian origin as well as 35 patients with UC and 62 healthy controls from the Chinese Han population.

RESULTS

No significant differences in the distribution of allele, genotype and haplotype frequencies were observed between C-318T and A+49G gene polymorphisms and IBD in Dutch Caucasians and UC in the Chinese Han population. Although the haplotypes of the C-318T and A+49G polymorphisms were distributed differently between Dutch Caucasian and Chinese Han populations, there were no differences in the subgroups of patients with CD classified according to age, localization and behaviour in the Vienna classification and in those with UC classified according to age at onset, disease extension and presence of colectomy in the Dutch patients. However, the CTLA4-318 genotype CC was more frequent in patients with CD over 40 years (93%) than in younger patients (74%) (P = 0.045).

CONCLUSION

C-318T and A+49G CTLA4 gene polymorphisms and their haplotypes are not associated in Dutch Caucasian patients with IBD and in Chinese patients with UC.

Abnormal expression of CTLA-4 by T cells from patients with myasthenia gravis: effect of an AT-rich gene sequence

Cytolytic T lymphocyte-associated antigen-4 (CTLA-4) plays a critical role in the down-regulation of antigen-activated immune responses. The aberrant CTLA-4 expression is characterized by low surface and intracellular levels of CTLA-4 protein, impaired up-regulation of CTLA-4 in T cells in response to ConA stimulation and high levels of soluble CTLA-4 (sCTLA-4) in serum. The serum levels of sCTLA-4 are positively correlated with the serum concentration of antibodies against the acetylcholine receptor. The (AT)(n) polymorphism in the 3'-untranslated region contributes to decreased mRNA stability and, hence, to reduced expression of CTLA-4.

Gamma interferon and granulocyte/monocyte colony-stimulating factor prevent endotoxin tolerance in human monocytes by promoting interleukin-1 receptor-associated kinase expression and its association to MyD88 and not by modulating TLR4 expression

Endotoxin tolerance is characterized by a decreased production of proinflammatory cytokines by cultured leukocytes in response to lipopolysaccharide (LPS) following a first exposure to the same stimulus. Gamma interferon (IFNgamma) and granulocyte/monocyte colony-stimulating factor (GM-CSF) are immunostimulatory cytokines that prime monocytes and prevent endotoxin tolerance. In this study, we show that the deactivating effects of LPS, as well as the priming effects of IFNgamma and GM-CSF or their capacity to restore tumor necrosis factor (TNF) production by LPS-tolerized human monocytes are independent of the modulation of TLR2, TLR4, or MD-2. In monocytes pretreated with IFNgamma or GM-CSF, interleukin-1 receptor-associated kinase (IRAK) expression is up-regulated. After LPS stimulation, an increased IRAK kinase activity, a higher MyD88/IRAK association, and a stronger NF-kappaB activation are observed. In contrast, in LPS-tolerized monocytes, IRAK expression and kinase activity, IRAK/MyD88 association, and NF-kappaB activation are inhibited. Furthermore, the prevention of tolerance by IFNgamma and GM-CSF was independent of IRAK kinase activity. Our results suggest that these cytokines prevent endotoxin tolerance induced by low but not by high doses of LPS by inhibiting IRAK degradation and by promoting its association with MyD88 after a second LPS stimulation, which in turn leads to NF-kappaB activation and TNF production.

MRP 8/14 and procalcitonin serum levels in organ transplantations

OBJECTIVES

MRP8/14 is a heterodimer of two myeloid calcium-binding proteins associated with different types of acute inflammatory processes. We studied MRP8/14 together with procalcitonin (PCT) serum levels in order to diagnose infectious complications or the rejection process affecting kidney or heart allograft.

METHODS

A total of 419 serum samples was evaluated. MRP8/14 levels were measured by ELISA (BMA Biomed), PCT by a sensitive immunoluminiscent assay ILMA (Brahms Diagn.)

RESULTS

Both parameters showed very low basal levels in healthy subjects (range 303-1,660 ng/ml of MRP8/14; less than 0.08 ng/ml of PCT). A rapid increase in serum levels occurred in response to bacterial infections (MRP8/14 up to 6,230 ng/ml; PCT up to 297 ng/ml). Serum PCT concentration remained low in the presence of kidney allograft rejection, where MRP8/14 levels were increased. An uncomplicated outcome of kidney or heart transplantation did not change basal serum MRP8/14 and PCT levels.

CONCLUSIONS

We conclude that 1) both MRP8/14 and PCT are very sensitive markers of complications in organ transplant recipients (normal values in uncomplicated outcome) 2) combination of both parameters is useful to discriminate between rejection (increased MRP8/14 with normal PCT) and systemic bacterial infection (both parameters increased).